Gas Spring

ABSTRACT

The invention consists of a gas spring which can absorb movements perpendicular to its operating axis. To do that, it has a hollow cylindrical body ( 1 ) with an open end, a piston rod ( 2 ) located in the hollow cylindrical body ( 1 ) which can be moved therein and a sliding element ( 3 ) connected to the free end of the piston rod ( 2 ) and laterally displaceable with respect thereto. It also has a connection means ( 4 ) between the sliding element ( 3 ) and the piston rod ( 2 ) which comprises an internal part which is located inside the piston rod ( 2 ) and an external part ( 5 ) which projects out of the free end of the piston rod ( 2 ), the sliding element ( 3 ) being situated on the free end of the piston rod ( 2 ) and the sliding element ( 3 ) and the connection means ( 4 ) being configured so that the sliding element ( 3 ) is laterally displaceable with respect to the external part ( 5 ) of the connection means ( 4 ).

OBJECT OF THE INVENTION

The object of the invention is a gas spring which can absorb movements perpendicular to the operating axis thereof.

BACKGROUND OF THE INVENTION

Gas springs are applied during sheet shaping processes, limiting the stress exerted thereon and making it possible for there to be displacement of the shaping tools with a slight increase of force.

The dies wherein these gas springs are installed tend to have guidance suitable to the functions thereof; however, specific parts thereof can have slight horizontal oscillations within its vertical movement actuated by the press. These types of horizontal oscillations are generally caused by floating plates used to hold the sheet piece while work is done thereon, or due to vibrations of the die itself when very localized stresses are made on a part thereof and not completely offset.

In order to resolve this problem, the use of a spherical surface on the end of the mobile axis is known which permits a certain slope oscillation of the support on the gas spring and permits a certain displacement due to the lesser friction factor of those surfaces. Nevertheless, this solution presents the drawback that the surface can make a print on the die, deforming it and reducing the operational stroke.

Also known is another solution which has one or two sliding elements inserted into a mechanized box at the end of the piston rod which permits the absorption of the previously described movements perpendicular to the operating axis of the piston rod.

The present invention proposes an alternative solution to those mentioned above which resolves the aforementioned drawbacks.

DESCRIPTION OF THE INVENTION

The gas spring object of the invention is of the type which comprises a hollow cylindrical body with one open end and a piston rod located inside the hollow cylindrical body which can be moved therein through its open end. The spring further comprises a sliding element connected to the free end of the piston rod and laterally displaceable with respect thereto, so that it permits the absorption of movements perpendicular to the operating axis thereof.

The spring that is object of the invention further comprises a connection element between the sliding element and the piston rod which comprises an internal part which is located inside the piston rod and an external part which protrudes from the free end of the piston rod. The sliding element is also situated on the free end of the piston rod, and the sliding element and the connection element are configured so that the sliding element is laterally displaceable with respect to the external part of the connection element.

The gas spring is going to be compressed by means of the action of a force on the sliding element, which in turn transmits the force to the gas spring, which displaces the piston rod to the inside of the gas volume of the hollow cylindrical body, compressing it and increasing its pressure and, therefore, the force of the gas spring. If the piece in contact with the sliding element suffers an oscillation in a direction perpendicular to that of the movement of the piston rod of the gas spring during that compression process, the sliding element will accompany that oscillation, but the force transmitted to the gas spring will continue to have the same component in the direction of the movement of the piston rod thereof.

The connection element between the sliding element and the piston rod also permits the sliding element to be fastened when the piston rod is in a reversed position and also facilitates the removal of the gas spring for maintenance work.

DESCRIPTION OF THE DRAWINGS

In order to complement the description being carried out and with the purpose of helping towards a better understanding of the characteristics of the invention, in accordance with a preferred example of practical embodiment thereof, a set of drawings is attached as an integral part of said description wherein the following, in an illustrative and non-limitative character, has been represented:

FIG. 1 shows a frontal schematic view of a first example of embodiment of the gas spring.

FIG. 2 shows a schematic and enlarged cross-section of the upper part of the piston rod corresponding to the example of embodiment from FIG. 1.

FIG. 3 shows a frontal schematic cross-section of a second example of embodiment of the gas spring.

PREFERRED EMBODIMENT OF THE INVENTION

FIG. 1 represents a frontal view of an example of an embodiment of a gas spring which comprises a hollow cylindrical body (1), a piston rod (2) located in the hollow cylindrical body (1) and which is displaceable therein through its open end and a sliding element (3) connected to the free end of the piston rod (2) and laterally displaceable with respect thereto.

FIG. 1 features a first example of embodiment wherein the sliding element (3) is formed by a single body. The connection element (4) between the sliding element (3) and the piston rod (2) comprises an internal part which is located inside the piston rod (2) and an external part (5) which projects from the free end of the piston rod (2). The sliding element (3) is situated on the free end of the piston rod (2), and therefore projects out from the upper part of the piston rod. The sliding element (3) and the connection element (4) are configured so that the sliding element (3) is laterally displaceable with respect to the external part (5) of the connection element (4). That is, the connection element (4) is solidly joined to the piston rod (2) and the sliding element (3) is displaced with respect to the connection element (4) as it is subject to a horizontal force.

In the example of embodiment shown in the figures, the connection element (4) is located in the centre of the piston rod (2) and the sliding element (3) is disposed surrounding the external part (5) thereof (4).

The connection element (4) incorporates a central threaded orifice (11) for maintenance which permits the insertion of a threaded element and therefore the removal of the gas spring (1).

In order to enable the sliding element (3) to move with respect to the external part (5) of the connection element (4), there is a space between both elements (5, 3).

The sliding element (3) has a greater height than the external part (5) of the connection element (4) so that the piece which rests on the spring will make contact with the sliding element (3).

The connection element (4) also fulfils the function of fastening the sliding element (3) when the spring is located in reversed position. To do this, the connection element (4) and the sliding element (3) are configured so that the connection element (4) comprises a projection (6) corresponding to a recess (7) of the sliding element (3).

Finally, the spring comprises an elastic element (8) between the external part (5) of the connection element (4) and the sliding element (3) to centre the sliding element (3).

In FIGS. 1 and 2, a first example of embodiment is represented wherein the sliding element (3) is solely capable of absorbing loads lateral thereto (3); for this reason, the free surface of the piston rod (3) is straight, in correspondence to the adjacent surface of the sliding element (3).

In FIG. 3, a second example of embodiment is represented wherein the sliding element (3) can absorb lateral loads and also achieves the adaptation to non-perpendicular thrust planes to said piston rod (2) of the gas spring.

To do that, the sliding element (3) comprises a first body (9) and a second body (10) situated between the first body (9) and the free surface of the piston rod (2), with at least one of the bodies (9, 10) having a convex support surface corresponding to another concave support surface of the adjacent element (2, 9, 10) so that the sliding element (3) has a lateral displacement and a displacement in the direction of the concave surface.

FIG. 3 represents the case wherein it is the second body (10) that has the aforementioned convex surface corresponding to the concave surface of the upper part of the piston rod (2). Preferably, the concave and convex surfaces are spherical.

Therefore if, additionally, the direction of movement of the piece in contact with the sliding element (3) suffers an oscillation during that compression process so that the thrust plane is not perpendicular to that of the movement of the piston rod (2), the first body (9) of the sliding element (3) will accompany that oscillation thanks to the second body (10), so that the force transmitted to the gas spring will continue to have the same component in the direction of the movement of the piston rod thereof. 

1. A gas spring which comprises: a hollow cylindrical body with an open end, a piston rod located in the hollow cylindrical body which is displaceable therein through the open end thereof, a sliding element connected to the free end of the piston rod and laterally displaceable with respect thereto, wherein it further comprises a connection element between the sliding element and the piston rod which comprises an internal part that is located inside the piston rod and an external part which projects from the free end of the piston rod, with the sliding element being situated on the free end of the piston rod and the sliding element and the connection element being configured so that the sliding element is laterally displaceable with respect to the external part of the connection element.
 2. The gas spring, of claim 1, characterised in that the connection element is located in the centre of the piston rod and the sliding element is disposed surrounding the external part thereof.
 3. The gas spring of claim 1, characterised in that it comprises a space between the external part of the connection element and the sliding element for the lateral displacement of the sliding element.
 4. The gas spring of claim 1, characterised in that the sliding element has a greater height than the external part of the connection element.
 5. The gas spring of claim 1, characterised in that the connection element and the sliding element are configured so that the connection element comprises a projection corresponding to a recess of the sliding element for the fastening thereof.
 6. The gas spring of claim 1, characterised in that it comprises an elastic element between the external part of the connection element and the sliding element.
 7. The gas spring of claim 1, characterised in that the free surface of the piston rod is straight, in correspondence with the adjacent surface of the sliding element.
 8. The gas spring of claim 1, characterised in that the sliding element comprises a first body and a second body situated between the first body and the free surface of the piston rod, at least one of the bodies comprising a convex support surface corresponding to another concave support surface of the adjacent element so that the sliding element is laterally displaceable and displaceable in the direction of the concave surface with respect to the piston rod.
 9. The gas spring of claim 8, characterised in that the second body comprises a convex surface corresponding to the adjacent concave surface of the piston rod.
 10. The gas spring of claim 1, characterised in that the connection element comprises a central threaded orifice for maintenance which permits the removal of the gas spring. 